Daytime Running Lamp Control Unit: Description and Operation

The Daytime Running Lamps (DRL) System operates the vehicle's High Beam Headlamps at reduced power during the daytime to make the vehicle more visible to other drivers.

With the Ignition Switch in RUN, the park brake released, and the Headlamps turned OFF, the DRL Module outputs a pulsing voltage at pin 8 to operate the High Beam Headlamps at reduced intensity. When the DRL System is operating, the Hi Beam Indicator is not illuminated.

Applying the park brake or turning on the Headlamps disables the DRL System. Applying the park brake grounds pin 6 of the DRL Module. Turning on the Headlamps in the low beam position applies battery voltage to pin 7 of the Module (and removes the ground input that the DRL Module senses through the Low Beam Headlamps). Turning on the Headlamps in the high beam position applies 12 volts to pin 8 of the DRL Module.

The DRL System is used only on vehicles sold in Canada.

NOTE: The headlamps may flicker during engine start-up and shut-down on DRL-equipped vehicles if the A/C-Heater Blower Motor is turned ON. This is a normal condition.

Also, during Low Beam Headlamp operation on a DRL-equipped vehicle, the Hi Beam Indicator will not illuminate when using the flash-to-pass feature.